1. Field of the Invention
The present invention relates generally to buildings and more specifically to a seamless sheet installation around roof structural members, which does not require the use of multiple lengthwise sheets to contain insulation between roof structural members and increases safety of the workmen installing and sealing sheet materials, roof insulation and roofing materials.
2. Discussion of the Prior Art
More stringent energy conservation codes are requiring much greater installed insulation thicknesses with greater installed insulation performances in building roofs and walls. These greater stringencies require different methods, which create space for greater thicknesses of insulation necessary to meet and exceed these higher thermal insulation requirements. Typically a sheet material is adhered or laminated to an insulation material such as fiberglass. This laminated insulation sheet material is installed between the exterior roof structural members and supported by steel straps which are installed substantially perpendicular, across the underside of the roof structural members such as metal building roof purlins. The side edges and end butt junctions of each of the individual laminated insulation sheet materials are then required to be sealed together over the tops of roof structural members. This sealing of the sheet materials is to resist air leakage due to pressure differences and convection currents to achieve optimal thermal performance of the insulation and to prevent condensation within the insulation.
Currently, installation of a sheet material for retaining insulation is primarily completed from the exterior of the building in conjunction with the roof sheeting process. Sealing of the building roof and walls insulation against air and moisture infiltration is a necessary requirement for meeting the minimum required building thermal performance. These thermal performance requirements are attempted to be accomplished with the strips of sheet material adhered to compressible strips of insulation, which are typically installed sequentially with the roof sheets of the building. The strip of sheet material is wider than the insulation strip. The sheet material is of sufficient extra width on each side of the insulation strip to form side edge tabs. The side edge tabs must accommodate a total thickness of the insulation material for the roof, plus the additional side edge tab sheet material of sufficient width to effectively seal one side edge tab to the next adjacent side edge tab lapped over the outermost surface of the roof structural members. The installation process positions the sheet material strip, with the adhered insulation strip with the two opposing sheet material side edge tabs, between two adjacent structural members with the side edge tabs installed up the sides of the roof structural members, lapped and and sealed over the outermost surface of the roof structural members. This installation process is dangerous for a workman to perform, time consuming and expensive.
Failure to effectively seal the side edge tabs may result in air and water vapor leakage into the insulation cavity where it can spread throughout the roof insulation cavity where it may condense and result in accumulation of liquid water, the reduction of thermal performance and corrosion of roof structural members.
There is a similar need to effectively seal the multiple sheet materials together at abutted end joints. The current practice is simply hiding the abutted end joints from view above the building rafters. The multiple strips of sheet material are adhered to the strips of insulation and have side edge tabs that overlap for effective sealing, however the ends of these adhered sheet materials require the insulation materials to abut tightly together and effectively seal the abutted laminated insulation sheet material ends together. The operation must be done under foot, which is not practical to accomplish and typically the abutted ends are not sealed effectively, if at all.
Accordingly, there is a clearly felt need in the art for seamless sheet installation around roof structural members, which allows a single length of sheet material to be safely installed around a plurality of adjacent roof structural members to retain insulation between them and eliminate the danger and expense of sealing the multiple lengthwise sheet material side edge tabs together over the outer surfaces of every structural member of the roof. The single length of sheet material does not have insulation adhered to strips of sheet material and the abutted ends of the adjacent sheet material are easily and effectively lapped and sealed together above the building rafters beams. The single seamless sheet wrapped around a plurality of adjacent roof purlins and secured to building roof structural members provides safety to insulation and roof sheeting workmen for fall protection and protection from falling objects for workmen below.